Crankpin truing device



June 29,1948. RPOSTMA 2,444,308

CRANK PIN TRUING DEVICE v Filed April 3, 1947 2 Sheets-Sheet 1 fig. 1.

IN VEN TOR.

FfQ/I/f 7 P05 Lma BY 44m hf/5 ATTORNEY June 29, 1948. POSTMA A 2,444,308

CRANK PIN TRUING DEVICE Filed April 5, 1947 v 2 She ets-Sheet 2 INVENTOR.

Fun/f Post/f7 a Patented June 29, 1948 "2,444,36'8 exempt-N TRUING DEVICE Frank i 0stma, Patelson, II. Application Aiiril 3, 194%, serial $29,223

12 Claims.

This invention relates to devices for truin'g were journals bf crank shafts of internal comion enginesena the like without removing it e "er'ankshaft from the engine; The device of the invention afie'ctssu'ch mine by e cuttin z, epon which is ain fflarly effective in removing u 1"'orn the sufiac of the journal, whereby the b aring journal is enemy restored to a truly it this; cylindrical shape. More part cularly, Qt invention relates to an ifr'iprove'dliner and :l er assembly'ada' to be substituted for the b arin li'i 'rsof t e engine cenneetmg rod, such l'i erjasse'rnbly carrying on its inner journal confronting "surface at least one transver e cutting irllefit Whi'bh lfriblis S t 50k iffdm journal sue a e by a oornbihed planing and turning operation.

The journal trumg liner and liner a'sse'mbly of present invention dismay particular advantages in reshaping cranksha'ift orahkpin jo u r nals which have both become oer-erected and developed ridges therein. A typical example or sueh type orwearifiig er e'raiikpnrs is found in automobile engines, the tendency toward wearb ng' eausecl by the neri'o'dical nature of the load the bearing, and the ridges, particularly at the center of the journal; being caused by the eiesesee of one "or l Il QI'G oil grooves in the inner bearing surface; which cause the wear on the 'cran pm tobe greater on aeh side of the on gihdve fil al! ih th 'Z bffe ddilfloiding with Such gldOV. The dVlCBS", which have relied solely upon abrasive liners carried within the ebni eetmg rodbearing halves, have been rather ii emciem in the removing er suchiidges from the crank pin. obvimisiy, in such ease the abrad'i-n g liner wears locally in the zone of the ridge, and thus but small part of the liner is utiliz dat least in the initial 'part of the truin'g e t .1- B s des. b e nse me t- 1 req the successve use of several abrasive v elements the liners bereie theridge is removed,

Tins en-e furt er twee -e: the nvents win 1 of the cran'kbins to outof round condition 2 a Briefly the journal truing liner assembly of the invention consists of the combination of remjoy; able liner elements fitting within the separable halves of a journal bearing. Such liner assembly is preferably made; in two partsyone such fiart'fitting within each separable part of the -j'ourna1 bearing housing. Each liner half preferably provided with at least we transversely disposed cutting "element located on the inner surface thereof; the cutting element or elements on each liner part being so located that the cutting elements are spaced an appreciable distance from each other when the liner *parts "are placed, to- 'ether to form the liner assembly. It is possible, however, Within thesoop'e of the invention; to 120- sition all the cutting elements of the liner assembly on one liner part, the other liner part acting as a guide and feeding pressure applying means. 4

In the embodiment presently preferred each liner is provided with two transverse cutting elements symmetrical "about a central radial plane; the outtirrg elements being so spaced that they lie at substantially uniform intervals about the crankpin, the two linerparts being of identical configuration. such "construction is obviously economical, since both liner parts are the same, and is easy to use, since n'o'attention need be 'given to the placing of e particular liner partin 'agi'ven bearing half nor to the direction 'iri Which the crankshaft is to be rotated. v

The invention will be more readily understood by reference to "the 'aefiompan'ying drawing showing preferred embodiments of the liner and liner assembly of the inventioni'n which:

Figure 1 is a. View partially in side elevation and partially in section of the bearing end of. a connecting rod of a crankshaft, and the cranknih with which it cooperates with the journal 'truin'g liner assenibly of the invention in place; c

Figure 2 is 'a view in edge "elevation of one of the cutting liner elements employed in the liner assembly shown in Figure 1; 5

Figure 3 is a view in 'edgeelevation of st-second embodimentor' such liner element; t

Figure 4' is a. view bf "a further embodiment of tneelemeiit; i'md, v

Fiiiu'r 5 s View in 'e'dg'e elevation of a; fourth embodiment of the liner element of the invention. Figure I shows the manner in which the journal 'truin liner, shown more barticu'larly in Figure 2, is 'empieyed with "anbth'er such liner t'o form a. assembly in truing crankshaft journals. in Figure 1 the 'cranknin, shown in cross section, is egress-tea by he reference character 2, aigiart or the o ll nfiflg rdfleddsefanng therewith bein shown at 4. The crankpin bearing at the lower end of the connecting rod, shown generally at 6, has a top half 8 integral with the lower end of the connecting rod 4 and a separable lower half H! in the form of a bearing cap. The cap is retained on the bearing by means of the vertical retaining bolts l2 extending through flanges on the outer edges of the bearing halves, the lower bearing cap being retained by means of nuts Hi.

In use, a journal truing liner is substituted for the thin bearing lining in each bearing half. Since the top and bottom liners in Figure 1 are identical, the same reference characters are employed in designating the same parts of each. The liner as a whole, which is designated generally by the reference character l6, consists of a backing member or shell [8 of thin flexible metal, such shell being approximately semi-cylindrical in shape. One edge of such shell is provided with an integral shim 2!], having a transverse slot (not shown) therethrough for the reception of the bolt I2, the other edge of the shell being devoid of a shim. The upper and lower liners are placed in the bearing as shown, so that the two integral shims 20 lie on one side thereof.

Each liner shell is provided, in the embodiment shown, with two cutting elements 22 so located as to lie at substantially equal distances from a vertical radial plane through the crankpin, the cutting elements also being so located that when the two liner elements are assembled as shown at Figure 1, each opposite pair of cutting elements lie substantially on the same radial plane.

7 The character of the cutting elements 22 will be more readily apparent by reference to Figure 2,.

which shows one of the liners employed in Figure '1, and to Figure 3, which shows a modified liner in which the cutting elements are, however, the same as those in Figures 1 and 2. In Figures 1, 2, and 3, cutting elements 22 are in the form of generally radially extending lands each having the transverse cutting edge 28, designated the front cutting edge, on the left hand side thereof, and the transverse cutting edge 30, designated the rear cutting edge, on the right hand side thereof. Each of such edges is provided with relief from the surface of the orankpin 2. In this instance, -relief is provided by means of the hollow ground surface 34 which lies on a circle having a radius much smaller than that of the crankpin. The relief thus provided both the front and rear cuttin edges is shown in Figure 3 as being measured by theangleB, between a line through each cutting edge normal to the radius and a line through such edge tangent to the upper surface of the cutting element that adjoins the cutting edge.

Each forward and rear cutting edge is provided with a substantial positive rake, the front cuttin edges havin such positive rake On one side of radial planes therethrough and the rear cutting edges having such positive rake on the other side of radial planes therethrough. The rake of both the front. and rear cutting edges is shown in Figure 3 as both being equal to an angle A, which is 'measured between a radial plane through each cutting edge and a plane tangent with the forward face of the cutting element that adjoins such cuttingedge.

As a result of such construction, that is, the

.making of the cutting lements symmetrical about a central radial plane, the liners may be inserted in the bearing in either the top or bottom bearing halves thereof, and the engine crankshaft may be rotated in either direction. When movement of the crankpin journal surface relative to the cutting elements on the liner shown in Figure 2 is toward the right front cutting edges 28, thus having a positive rake relative to the crankpin, cut into the crankpin and shaves or peels away the material in the ridges thereof by a cutting operation which is a combined planing and turning operation. When rotation of the crankshaft takes place in the opposite direction, which may sometimes be desired, rear cutting edges 30 then having a positive angle of rake relative to the crankpin function as the cutting edges in the same manner as previously described in connection with edges 28.

It is generally desirable to employ on each liner an element, preferably located between the cutting elements, which combines the functions of a guide and depth gauge. In the embodiment shown in Figures 1 and 2, such guide and depth gauge takes the form of a comparatively stifi coated abrasive element 24 which may consist, for example, of an arcuate piece of vulcanized fiber to which abrasive grain is secured by a cured adhesive. To make the inner surface of the abrasive element 24 conform more exactly to the contour of the crankpin, such element may be backed up by a spacer 26, which is thicker at its center than at its ends. Elements 24 and 26 are preferably held in position on the liner by being snapped into place between the cutting elements 22, the liner being shown in solid lines in Figure 2 as being flattened somewhat to receive elements 24 and 26, following which upon release of the liner the natural spring of the shell l8 restores it to the shape shown in dotted lines in that figure. When an abrasive coated element such as 24 is employed as the guide and depth gauge, it has the further advantage that it contributes a useful metal removing action, so that metal is removed, by the embodiment of the liner and liner assembly shown in Figures 1 and 2, by combined metal cutting and abrading operations.

The metal cutting elements 22 in the embodiment in Figures 1, 2, and 3 may be formed, separately from the shell l8, from hard metal such as tool steel or Carboloy, which may be brazed,

soldered, or welded to the shell. The embodiment of the liner shown in Figure 3 is identical with that shown in Figures 1 and 2, with the exception that the guiding and depth gauging element, here shown at 32, is non-abrasive in character. Such element may conveniently be formed from a hard product such as vulcanized fiber, and may be retained in place between the cutting elements in the same manner as element 24.

Further embodiments of the liner of the invention are shown in Figures 4 and 5. In both these embodiments, a non-abrasive guiding and depth gauging member is employed, that in Figure 4 being designated 43 and that in Figure 5, B6. In Figure 4 the liner l6 has a shell 40, to one edge of which is affixed, the integral shim 42. In this instance, the cutting elements 44 are integral with the shell 40, being punched up therefrom by an operation which leaves a depression 54 on the outer surface thereof. Such cutting elements 44 7 other cutting edge having a positive rake on the other side of a radial plane therethrough.

8. As a new article of manufacture a journal truing liner for engine crankshaft bearings, such bearings being formed in separable halves and having means for holding such halves together,

said liner assembly comprising an arcuate outer carrier shell of relatively thin flexible metal adapted to seat against the bore of one half of the bearing and having at least one transverse cutting element on its inner surface the cutting element having at least one inwardly facing transverse cutting edge, and a guiding and depth gauging element adapted to engage the surface of the crankpin, said last named element lying on the inner surface of the shell in proximity to the cutting element.

9. As a new article of manufacture a journal truing liner for, engine crankshaft bearings, such bearings being formed in separable halves and having means for holding such halves together, said liner assembly comprising an arcuate outer carrier shell of relatively thin flexible metal adapted to seat against the bore of one half of the bearing and having at least two transverse cutting elements on its inner surface, the cutting elements being spaced circumferentially of the liners to an appreciable extent, each cutting element having at least one inwardly facing transverse cutting edge, and a guiding and depth gauging element adapted to engage the surface of the crankpin, said last named element lying on the inner surface of the shell between the cutting elements, the cutting edges of the latter elements projecting radially inwardly of the parts of the guiding and depth gauge element adjacent thereto, r

10. As a new article of manufacture a journal truing liner assembly for engine crankshaft bearings, such bearings being formed in separable halves and having means for holding such halves together, said liner assembly comprising a pair of arcuate outer carrier shells of relatively thin flexible metal adapted to seat against the bore of the bearing, each such liner element having at least one transverse cutting element on its inner surface intermediate its ends, the cutting elements being so located on the individual liners that when the liners are assembled they are spaced circumferentially of the bearing to an appreciable extent, each cutting element being in the form of a land having at least one inner edge, such edge being a cutting edge and having relief from the surface of the journal, such cutting edge also having a positive rake on one side of a radial plane therethrough, and a guiding and depth gauging element on each liner adapted to engage the surface of the crankpin, each of said last named elements lying on the inner surface of its shell in proximity to the cutting element on such shell.

11. As a new article of manufacture a journal truing liner assembly for engine crankshaft bearings, such bearings being formed in separable halves and having means for holding such halves together, said liner assembly comprising a pair of arcuate outer carrier shells of relatively thin flexible metal, each carrier shell adapted to seat against thebore of its respective half of the bearing, each shell having at least two circumferentially spaced transverse cutting elements on the inner surface thereof, the cutting elements being so located on the individual liners that when the liners are assembled in operative position they are spaced circumferentially of the bearing to an appreciable extent and pairs of cutting elements on the assembly lie substantially opposite each other on radial planes, each cutting element being in the form of a land having two inner edges, each such edge being a cutting edge and having relief from the surface of the journal, one cutting edge having a positive rake on one side of a radial plane therethrough, and the other cutting edge having a positive rake on the other side of a radial plane therethrough, and a guiding and depth gauging element on each liner adapted to engage the surface of the crankpin, each of said last named elements lying on the inner surface of its shell between and in proximity to the cutting elements on such shell, the inner crankpin engaging surface of the guiding and depth gauging element being made up of abrasive grains. 7

12. As a new article of manufacture a journal truing liner assembly for engine crankshaft bearings, such bearings being formed in separable halves and having means for holding such halves together, said liner assembly comprising a pair of arouate outer carrier shells of relatively thin flexible metal, each carrier shell adapted to seat against the bore of its respective half of the bearing, each shell having at least two circumferentially spaced transverse cutting elements on the inner surface thereof, the cutting elements being located on the two liners so that when the liners are assembled in operative position, pairs of cutting elements on the assembly lie substantially opposite each other on radial planes, each cutting element being in the form of a land having two spaced inner edges, each such edge being a cutting edge and having a relief from the surface of the journal, one cutting edge having a positive rake on one side of a radial plane therethrough, and the other cutting edge having a positive rake on the other side of a radial plane therethrough, and a guiding and depth gauging element having a smooth crankpin engaging inner surface on each liner, each of said last named elements lying on the inner surface of its shell between and in proximity to the cutting elements on such shell.

FRANK POSTMA. 

